St. Cynog's Church in Llangynog stands on the site of an early medieval foundation commemorating the fifth century martyr, Cynog, and first appears in the historical record during the Norwich Taxation of 1254, but all early buildings have been destroyed. The existing church was built in 1791/2, in the Georgian style with round-head doors and windows, and was then significantly restored in 1894 by William Spaull, with the restoration work characterised by two-centred arches. All that remains to indicate the original Georgian construction is the south doorway, and a blocked priests? door; all fixtures and fittings date to the nineteenth century reconstruction.

Despite its complete reconstruction, St. Cynog's maintains its medieval position within an early round churchyard at the centre of the village, and is likely to have been rebuilt upon earlier foundations. It is single chambered, with a north east vestry, south porch, and west bellcote, and constructed largely from local uncoursed slate with grey sandstone dressings. There are a number of Gothic features, including coped gables, and a square Gothic font within.

Source: Cadw Listed Buildings Record

K Steele, RCAHMW, 17 November 2008

2. The north-east vestry contains a number of slate memorial dating from between 1784 and 1851, presumably moved to the vestry during the late-nineteenth-century restoration.

(Sources: Information provided by a member of the public, CPAT, Montgomeryshire Churches Survey)
A.N. Coward, RCAHMW, 20.05.2019